Ramnik Singh

In vitro antioxidant activity of pet ether extract of black pepper

Objective: To investigate the in vitro antioxidant activity of different fractions (R1, R2 and R3) obtained from pet ether extract of black pepper fruits (Piper nigrum Linn.) Materials and Methods: The fractions R1, R2 and R3 were eluted from pet ether and ethyl acetate in the ratio of 6:4, 5:5 and 4:6, respectively. 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) radical, superoxide anion radical, nitric oxide radical, and hydroxyl radical scavenging assays were carried out to evaluate the antioxidant potential of the extract. Results: The free radical scavenging activity of the different fractions of pet ether extract of P. nigrum (PEPN) increased in a concentration dependent manner. The R3 and R2 fraction of PEPN in 500 µg/ml inhibited the peroxidation of a linoleic acid emulsion by 60.48±3.33% and 58.89±2.51%, respectively. In DPPH free radical scavenging assay, the activity of R3 and R2 were found to be almost similar. The R3 (100µg/ml) fraction of PEPN inhibited 55.68±4.48% nitric oxide radicals generated from sodium nitroprusside, whereas curcumin in the same concentration inhibited 84.27±4.12%. Moreover, PEPN scavenged the superoxide radical generated by the Xanthine/Xanthine oxidase system. The fraction R2 and R3 in the doses of 1000µg/ml inhibited 61.04±5.11% and 63.56±4.17%, respectively. The hydroxyl radical was generated by Fentons reaction. The amounts of total phenolic compounds were determined and 56.98 µg pyrocatechol phenol equivalents were detected in one mg of R3. Conclusions: P. nigrum could be considered as a potential source of natural antioxidant.

Performance Analysis of Fast Adders Using VHDL

This paper presents performance analysis of different Fast Adders. The comparison is done on the basis of three performance parameters i.e. Area, Speed and Power consumption. Further, we present a design methodology of hybrid carry lookahead/carry skip adders (CLSKAs). This modified carry skip adder is modeled by using both fix and variable block size. In conventional carry skip adder, each block consists of ripple carry adder and skip logic is used after each block to generate carry for next block. The speed of operation depends on carry propagation from previous block to next block. In CLSKAs, we use carry lookahead logic in each block to generate carry for next block. The modified carry skip adders presented in this paper provides better speed and power consumption as compare to conventional carry skip adder and other adders like ripple carry adder, carry lookahead adder, Ling adder, carry select adder. The modified carry skip adders with fix block require few more CLB’s because of Carry lookahead logic, whereas with variable block scheme, area optimization is achieved.